CPFAs of the present invention allow the creation of stable emulsions and hydrogels in a manner that is markedly more efficient than the conventional manufacturing processes in several respects. Conventional emulsion manufacturing processes requires two heated mixing vessels. The aqueous phase is weighed, staged and introduced into a first vessel. The oil phase is weighed, staged and introduced into a second vessel. Prior to being combined, the contents of the two separate vessels must each be heated to a temperature greater than the melt point of the highest wax in the emulsion, typically by 5 degrees Centigrade. If, for example, the aqueous phase is colder than the oil phase, waxes in the oil phase can crystallize. Further, in conventional emulsion manufacturing—particularly, complex multi-ingredient formulations—ingredients must be carefully weighed, added in specific order, and mixed for specific mixing times. Addition of one phase into another phase is often sensitive to the rate of addition. If two phases are combined too quickly, increased mixing time, and energy, is required to stabilize the emulsion.
Using CPFAs of the present invention is simpler and requires less energy. CPFAs of the present invention allow the two phases of the emulsion, aqueous and oil, to be combined into a single vessel, not two (or more) vessel, and thereafter mixed and heated to the desired temperature. Only one vessel needs to be heated (and cleaned). At low as well as high temperatures, the mixture containing CPFA is emulsified and homogenous. Moreover, crystallization of waxes does not occur when manufacturing emulsions (or hydrogels) using CPFAs of the present invention.
Importantly, in conventional manufacturing processes, the emulsion is not stabilized until the emulsion is cooled down. This “cool down” stage is critical. However, the rate and duration of cool down can impact the sensorial properties of the final finished product, often causing batch-to-batch variation. CPFAs of the present invention solve this problem, providing a streamlined process, with fewer addition steps, using only one vessel, with significantly lower energy requirements to create reproducible emulsions (and hydrogels).
Polyacrylic acids, polyacrylates, polycacrylate copolymers, polyacrylate crosspolymers, and their respective salts (collectively referred to in the present application as “Polyacrylic Acid Derivatives” and abbreviated as “PADs”)—components of the CPFAs of the present invention—are typically provided by suppliers of chemical raw materials in powder form and serve a number of functions in personal care formulations (as well as in paints and other surface coatings, adhesives, and textiles), including as aqueous rheology modifiers. However, when provided in powder form, PADs are not easily or thoroughly dispersed, and often form aggregates. To overcome these limitations, PADs are commonly sold as dispersions in a solvent also containing an emulsifier. When provided in the form of a dispersion, the powder is “plasticized”, and is thus more easily added to an emulsion to achieve the desired rheology. Typically, the solvent is petroleum derived (e.g., mineral oil or a hydrogenated alkene, such as polydecene, polybutylene, or squalene) and the emulsifier is ethoxylated. There is, however, a growing demand to reduce the use of petroleum derived ingredients, especially in personal care formulations. Accordingly, there is a need for being able to disperse PADs without petroleum-derived solvents and without forming aggregates. This need is met by the inventive compositions of the present invention. In personal care formulations, esters are among the most common ingredients—functioning as emollients and conditioners (e.g., Isopropyl Myristate), as solvents (e.g., Ethyl Acetate), as fragrance components (e.g., Methyl Salicylate), and as preservatives (e.g., Propylparaben). Caprylic/Capric Glycerides (“CTG”) is also widely used for its emollient properties, increasing the water content of skin by blocking the evaporative loss of water. However, PADs are known to have limited or no solubility in cosmetically acceptable esters or CTG. To the extent PADs could be mixed into such esters or CTG, the resultant sticky paste was very high in viscosity, too high to be used in the manufacture of personal care products. Accordingly, there is a need to be able to render PADs are directly soluble in cosmetically-acceptable esters and CTG, without a petroleum-derived solvent. That need is met by the compositions and methods of the present invention whereby PADs (and mixtures thereof) are combined specific minimum amount of one or a mixture of emulsifying waxes, which, in certain embodiments, are polyglyceryl esters, thereby rendering the PADs directly soluble in cosmetically-acceptable esters and CTG.